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https://issues.apache.org/jira/browse/AURORA-1868?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15803109#comment-15803109
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Mehrdad Nurolahzade commented on AURORA-1868:
---------------------------------------------
https://reviews.apache.org/r/55243/
> Evaluate multiple preemption proposals per round
> ------------------------------------------------
>
> Key: AURORA-1868
> URL: https://issues.apache.org/jira/browse/AURORA-1868
> Project: Aurora
> Issue Type: Story
> Components: Scheduler
> Reporter: Mehrdad Nurolahzade
> Assignee: Mehrdad Nurolahzade
> Priority: Minor
>
> {{TaskScheduler}} makes an attempt to preempt already identified candidates
> through {{Preemptor}} when it fails to schedule a task. However,
> {{Preemptor}} currently evaluates only one candidate per invocation. A
> candidate may get vetoed at this point by scheduling filters. If a candidate
> fails validation the task group might get penalized by {{TaskGroups}} to give
> {{PendingTaskProcessor}} some time to find new preemption candidates; despite
> the fact that such a candidate may already exist in slotCache. This penalty
> can result in expiration of {{slotCache}} entries, hence slowing down the
> overall preemption process.
> Consider modifying {{Preemptor}} so that it evaluates all existing preemption
> candidates before giving up. This improvement comes at the price of reduced
> scheduling throughput. However, in a near capacity cluster, reduced
> scheduling throughput is far more acceptable than failure to schedule
> critical production services.
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